Comparison
BusyWait and OneCal
This is the genuinely close one. OneCal and BusyWait are the same kind of product — sync several calendars, get a booking link backed by all of them — and anyone choosing between them is choosing between two tools that solve the same problem.
The honest summary is that OneCal is the more established product and BusyWait is the more restrictive one, deliberately. Most of the differences below follow from that.
Credit where it is due
What OneCal does better
Written first, because a comparison that never concedes anything is not worth reading.
- Maturity. OneCal has been running for years, with the support history, documentation and accumulated edge-case handling that come with it. BusyWait has none of that yet, and no amount of writing changes it.
- Being a known quantity. There are people you can ask about OneCal and reviews you can read. There is very little to find about BusyWait.
- Breadth of sync configuration. It has had longer to accumulate options for how a sync behaves.
Side by side
The differences that decide it
| OneCal | BusyWait | |
|---|---|---|
| Free tier | Trial, then paid | Two calendars and one sync, free indefinitely |
| Default event payload | Configurable, with more than busy available | Start, end and busy. Anything more is switched on per sync, never per account and never by default |
| Calendar providers | Google and Outlook | Google, Outlook, iCloud and any CalDAV server, including Fastmail and Proton |
| Booking links | Included | Included from Pro |
| Published failure behaviour | Documentation and support | A page setting out every failure mode, how you are told, and what happens if the product is wound down |
| AI features | Not a focus | None, and none planned |
Which one
How to decide
Choose OneCal
Choose OneCal if you want the more proven product, if you need a sync option BusyWait does not have, or if being able to find other people who use it matters to you. Those are good reasons and a new product cannot argue with them.
Choose BusyWait
Choose BusyWait if you need iCloud or CalDAV, if you want to try the thing properly without a trial clock, or if you want the busy-only floor to be the default rather than a setting you have to find and maintain.
FAQ
Questions about the two
- What is the difference between BusyWait and OneCal?
- Both sync multiple calendars and offer booking links backed by all of them. The practical differences are that BusyWait connects to iCloud and any CalDAV server such as Fastmail or Proton as well as Google and Outlook; that it has a free plan for two calendars which does not expire, rather than a trial; and that a mirrored event carries only a start time, an end time and the status busy unless you switch more on for that specific sync. OneCal is the older and more established product, with a longer support history.
- Is there a free calendar sync tool that connects iCloud?
- BusyWait has a free plan that syncs two calendars with one sync, free indefinitely rather than as a trial, and it connects Google Calendar, Outlook, Apple iCloud Calendar and any CalDAV server including Fastmail, Proton and self-hosted setups. Mirrored events carry a start time, an end time and the status busy by default, with no title, guest list or notes unless you enable them for that sync.
Two calendars, free, for as long as you like
Not a trial. Enough to find out whether the thing described above is the thing you wanted.